The invention relates to a CMOS imaging facility implemented on a substrate through a set of pixel circuits that are array-wise organized in lines and columns and each comprise a radiation-to-charge accumulator, a transfer transistor for transferring a representation of said charge, a reset transistor fed by a reference voltage and a source follower transistor for feeding a select transistor that feeds said representation to an output array conductor, such as being recited in the preamble of claim 1. It is to be noted that in this application CMOS imaging facility means that the imaging facility is based on CMOS (=Complimentary Metal Oxide Semiconductor) technology or on NMOS technology or on PMOS technology. In CMOS technology both NMOS and PMOS technology is used. This kind of imaging facility has become a predominant technical feature for use by the general public. Generally, the pixels are scanned in a line-wise organization for display, broadcasting or storage. In principle, the usage of the terms lines and columns can hereinafter be interchanged.
Now, a first scanning organization is progressive, wherein the lines are scanned in the order #1, #2, #3, #4, etcetera. A second scanning organization is according to #1, #3, #5, . . . , #2, #4, #6, . . . , #1, etcetera, such as being originally based on the well-known interlaced color television broadcast technology. The odd lines will then constitute a first field of the first frame, then the even lines will constitute the second field of the first frame, and so further for consecutive frames. The above means that normally, between the first field of a frame and the second field of the same frame there is an off-set in time (roughly equal to the field-scanning interval), and also an off-set in vertical position (roughly equal to the width of one scanning line.
Now, the present inventor has recognized that the constituting of each single pixel from the charge accumulation result of two adjacent accumulator elements would raise the resulting signal by a factor of two, which would accordingly increase the signal-to-noise ratio by a relative factor of two, and in doing so to a large degree would inhibit the producing or retaining of unwanted noise and other interferences.
Therefore, according to one of its objects, the invention envisages to systematically join or share the charges accumulated for various pixels thereamongst, for so averaging statistical effects and the like.